The invention relates generally to a center beam railway car, and particularly to a center beam railway car adapted for reducing chafing of lading.
Center beam railway cars typically comprise a floor surface supported by a pair of trucks, a bulkhead disposed proximate each end of the car, and a longitudinally extending vertical center beam structure. Lading is usually placed on the floor surface along both sides of the center beam structure. If the lading is in bundles, multiple bundles are typically stacked up to the height of the center beam structure. The lading is usually stacked against the center beam structure to provide lateral support therefor. An example of a center beam railway car is disclosed in U.S. patent application Ser. No. 09/635,978, filed Aug. 9, 2000.
To help secure the lading relative to the railway car, straps or cables may extend over the lading. The straps or cables exert most of their forces on the uppermost bundles of lading, urging the uppermost bundles both downward and inward against the center beam structure.
In the transportation of lading on center beam railway cars, chafing can occur between the bundles of lading and the railway car. In particular, it has been found that the top 12xe2x80x3 to 18xe2x80x3 of the uppermost bundles are subject to considerable chafing. Chafing may result in undesirable damage to the lading. For example, if the lading comprises bundles of lumber wrapped in plastic sheeting, the innermost piece or pieces of lumber on the uppermost bundle may rub against the center beam structure and become damaged. Furthermore, the plastic sheeting may tear due to the chafing or rubbing, allowing moisture into the wrapped bundle of lumber. The lumber may become marred with mildew or mold if moisture enters the bundle through a torn plastic wrapping. Damage to the lading caused by chafing contact with the center beam structure may be even more substantial on trips of greater length.
Chafing between the lading and the center beam structure may not only damage the lading, but also the center structure. The center beam structure, like the majority of the railway car, is usually painted to help protect the railway car from rusting. When the bundles of lading rub against the painted center beam structure, the paint may rub off or become worn away, exposing the steel underneath to rusting. Furthermore, a rusty center beam structure may cause undesirable rust staining of any exposed lumber rubbing thereagainst.
The chafing may be largely due to movement of the lading relative to the center beam structure of the railway car. This movement may be both vertical and horizontal. The relative movement may be due to either or both shifting of the lading and flexure of the center beam structure. The movement of the center beam structure relative to the remainder of the car can be particularly acute near the top of the structure, and near the longitudinal midpoint of the structure.
Numerous attempts have been made to reduce chafing between the lading and the center beam structure of a center beam railway car. For example, center beam cars having lowered center beam structures have been made to attempt to reduce chafing of the lading. The uppermost bundles of lading can be stacked above the shortened center beam structure and against each other to eliminate contact of the uppermost bundles with the structure. However, it has been found that chafing may still result from contact between adjacent, uppermost bundles of lading during transportation.
It has also been suggested that chafing may be reduced by reinforcing center beam structures to reduce movement of the structure relative to the remainder of the railway car during transportation. While reinforced center beam structures may reduce movement of the structure, they add significantly to the weight of the railcars and may reduce the total weight of lading that can be transported. Furthermore, unless all relative movement between the lading and the center structure is eliminated, chafing may still occur.
Other suggestions have included placing stationary or movable plastic pads between the lading and the center beam structure. One test was performed by attaching plastic pads formed of ultrahigh molecular weight (UHMW) polypropylene along a center beam structure of a center beam railway car. Lading was then placed along the center structure and the car was subjected to 10,000 cycles of 2500 pounds of force to simulate loads that may be experienced by the lading during a typical trip. Not withstanding the pads, the uppermost bundles were still severely damaged by chafing against the center structure.
Accordingly, there remains a need for reducing the chafing and resulting damage of lading transported by center beam railway cars.
In accordance with the invention, a center beam railway car is provided that is adapted to reduce chafing between lading and a center beam structure. The railway car may include apparatus to significantly reduce or eliminate chafing of the lading due to both vertical and horizontal relative movement between the lading and the center beam structure.
In an embodiment of the invention, chafing between the center beam structure and the lading may be reduced by providing roller members between the center structure and the lading. The roller members may be adapted to reduce or eliminate friction between the lading and the center structure.
In an embodiment of the invention, the rollers may be mounted to the center beam structure such that friction is reduced due to both horizontal and vertical relative movement between the lading and the center structure. The roller may comprise a roller member rotatably mounted around a shaft. The roller member may comprise a hollow cylinder having an outer surface for contacting the lading and an inner bore for receiving the shaft. Preferably the shaft has a diameter smaller than the inner bore of the roller member to provide sufficient clearance therebetween to allow the roller to freely rotate relative to the shaft. One or more bearings or bushings may be disposed between the shaft and the roller member to reduce friction therebetween. The bushing may comprise a non-metallic polymer sleeve for reducing maintenance. Opposing ends of the shaft may be fixed relative to the center beam structure.
The center beam structure may comprise a plurality of upstanding vertical post members having a top chord connecting their upper ends. Diagonal brace members may be arranged between adjacent or other select post members to further strengthen the structure.
The shafts of the rollers may be mounted between the vertical post members with brackets. The use of brackets may be desirable because minimal modifications to the center beam structure may be required, simplifying the retrofitting of existing center beam railway cars with the rollers of the invention. Horizontal lower brackets may be provided between adjacent post members for supporting the lower ends of the shafts. A hollow tube may extend upwardly from the lower bracket for receiving the lower end of the shaft to secure the shaft relative to the lower bracket. A horizontal upper bracket may be welded between downwardly extending legs of the top cord for supporting the upper end of the shaft. The upper bracket may include a hole for insertion of the upper end of the shaft.
In an embodiment of the invention, the roller member may have a recess at either its upper end, lower end, or both ends for receiving a spring. When the roller is mounted between the upper and lower brackets, each spring biases the roller member either downwardly or upwardly relative to the shaft, allowing the roller member to translate vertically to accommodate vertical movement of the lading relative to the center beam structure. In addition, the spring may assist in maintaining the roller securely mounted between the upper and lower brackets. For example, to insert the roller the upper end of the shaft may be pushed upward into the aperture formed in the upper bracket until the lower end of the shaft is able to clear the tube on the lower bracket for insertion therein. The spring will then bias the roller member into a preferred orientation relative to the lower bracket.